#extension GL_OES_EGL_image_external : require //声明使用扩展纹理
precision mediump float; //声明数据类型为float
uniform samplerExternalOES videoTex; //纹理采样器
varying vec2 textureCoordinate; //由顶点着色器传递过来的纹理坐标属性
void main() {
    gl_FragColor = texture2D(videoTex, textureCoordinate);//纹理采样
}